Hypertension is abnormally high blood pressure and is one of the most common diseases afflicting humans. If left untreated, hypertension leads to multiple organ damage and is associated with much morbidity and mortality worldwide. Hypertension is an important risk factor for coronary heart disease, stroke, congestive heart failure, end-stage renal disease, and peripheral vascular disease.
Hypertension is defined with respect to systolic and/or diastolic pressure and may be either essential or secondary. Essential hypertension is hypertension where there is no identifiable secondary cause. Approximately 95% of American adults with hypertension have essential hypertension, while secondary hypertension accounts for fewer than 5% of the cases. The pathogenesis of essential hypertension is complex, and the factors involved may vary from patient to patient. Such factors could include, for example, abnormalities in blood vessel elasticity or resistance, cardiac output, circulating blood volume, and circulating hormone levels. Hypertension is most commonly treated by lifestyle modifications (e.g., diet and exercise) and various pharmacological agents. These treatments are not always effective in certain patients, however, and blood pressure medications are not without significant side effects.